1. Field of the Invention
The present invention relates to a laminated glass and preparation thereof used for front glass or side glass of a car, and window glass of a building.
2. Description of the Related Art
There has been generally used a resin of polyvinyl butyral as an intermediate layer of laminated glass, wherein there have been following problems as thermoplastic resin:
1. The glass plates are slipped with each other, or foams are generated by heat after laminating, drived from comparative low softing point of polyvinyl butyral.
2. The laminated glass is gradually whitened from periphery thereof, and adhesion power of glass plate is lowered by exposing in a high humidity atmosphere for a long period of use, which is drived from property of the resin easily affected by moisture.
3. Character of impact resistance of the resin depends upon temperature thereof, pierce resistance is lowered rapidly, particularly, at higher than room temperature, such as higher than 30 degree C.
In order to solve the above problems of resin of polyvinyl butyral, the present inventors provided a laminated glass prepared by providing a thermosetting resin of ethylene-vinyl acetate copolymer to which an organic peroxide is added, between glass plates, and thermosetting the resin to cure and to integrate them; which was applied as a patent application (for example: Japanese Unexamined Patent Publication No. 57-196747).
Further, the present inventors provided a laminated glass prepared by inserting a film composed of an organic resin between the intermediate layers of glass plates to improve impact and pierce resistance thereof, and to make design onto the film or to give character of reflecting and absorbing heat ray by coloring onto the film; which was applied as a patent application (Japanese Unexamined Patent Publication No. 60-226436). The laminated glass utilizes a very high adhering power of the intermediate layer of resin of polyvinyl butyral to the glass and the film of organic resin.
A laminated glass improved in impact and pierce resistance by using a thermosetting resin of ethylene-vinyl acetate copolymer with addition of a hydrocarbon resin and an organic peroxide was provided, and applied as a patent application (Japanese Unexamined Patent Publication No. 3-183645).
As problems of conventional laminated glass, however, it is pointed out that:
First problem: when the laminated glass is given a strong impact power so as to rupture glass, for instance, in using for front glass of a car, impact onto a head of a driver is too large, or it has large resiliency as structure material of the laminated glass;
Second problem: when an oraganic resin film is inserted into an intermediate layer of glass plates, it is expected to give an effect of sound insulating glass, however, it is pointed out that so large effect cannot be expected. Recently, it is recognized as an important item that a comfortable driving circumstances can be formed by insulating sound of out door, such as sound of engine, by using the laminated glass for car, and a comfortable residing circumstances can be formed by insulating sound of out door and in door also by using the laminated glass as window glass.
In transparency of the laminated glass, it is no problem in using as a laminated glass for construction, however, in using it for a front glass of car requiring a high transparency, it remains a little room to improve.
It was provided that dibenzylidene sorbitol and/or tribenzylidene sorbitol can be used as additive to improve transparency of polyolefin resin,(Jananese Examined Patent Publication No.61-48536, and No. 64-413), however, that is addition of dibenzylidene sorbitol and/or tribenzylidene sorbitol into thermoplasic resin of polyolefin, and the transparency of the improved compsition is only 20% order in haze value, giving not so satisfied use of it in laminated glass.
The above-mentioned laminated glass of prior application (Japanese Unexamined Patent Publication No. 3-183645) can have original properties of laminated glass, such as, a high safety, hard to pierce by impact of a material, hard to splinter, and prevention from invader and thief into building, however, recently desired functions of glass, such as, prevention from ultra violet ray which is desired in a recent high quality and intelligent building and residence, that is, inhibition of furniture, curtain, carpet and mat from colour fade-out, and protection of exhibiting goods in show window, cannot be expected.
It is an object of the present invention to solve the above-mentioned problems of conventional art and prior art, and to provide a laminated glass having a small impact onto human body when the glass is used as window glass of a building or a car, and having an excellent function of sound insulation and sound proof.
Another object of the present invention is to provide a laminated glass having an excellent impact and peirce resistance, a high safety, and a superior transparency.
A futher object of the present invention is to provide a laminated glass having an excellent impact and peirce resistance, and a superior absorbing property for ultra violet ray.
A futher object of the present invention is to provide a method for easily and efficiently preparing laminated glass having an excellent impact and peirce resistance, and a high safety, in a high productivity.